Study On Numerical Simulation Of Groundwater And Optimal Allocation Of Water Resources In Luanjing Irrigation Area, Inner Mongolia

This thesis is based on the research of National natural science funds-the recharge of deep-buried phreatic water from irrigation by the Yellow River and environment benefit of irrigation by the Yellow Rive(r26600302). Inner Mongolia is one of the driest areas in China. Luanjing Irrigation Area is adjacent to the Teng Ge-li Desert where evaporation is large and precipitation is small, so the area is seriously short of water and if we want to develop agriculture we must depend on irrigation.First of all, rainfall (irrigation) recharge hysteresis quality is analysed at phreatic water deep zone, deep vadose zone has a strong storage capacity, when the diving depth more than 4m, the amount of recharge is not with the change of depth, and the amount of irrigation recharge can get in accordance with the principle of water balance; irrigation water infiltrated to groundwater lasted about 240-360d of study area. is estimated using the penetration speed and depth.Secondly, the smallest amount of irrigation recharge as the basic aim of the irrigation area, and in meeting the agricultural development, economic development, requirements to food production, requirements to other types of crop production, it optimizes the planting area and cultivation structure, models and solves with GAMS software, then the optimum structure and acreage planted are obtained.Thirdly,based on the learning of the groundwater system boundaries,environmental features and characteristics of the internal structure, it set up a hydrogeological conceptual model of the study area, and a mathematical model is set up by the conceptual model; two-dimensional model of the study area is set up with visual MODFLOW software,and doing the model parameters rating and testing.Fourthly,it is predicted that the ground water level for the next 10 years.Because of the impact of irrigation, the ground water level increases markedly; after the planting structure adjustment, as a result of the amount of recharge reduced, the water level rising is significantly reduced, it will help mitigate the occurrence of soil salinization, but the issue of soil salinization is still being,so it must change the existing irrigation methods or take appropriate measures to control the project.Finally, a drainage area is set up in downstream, after establishing the irrigation areas, the water level declines in the irrigated areas downstream and it is a funnel so that the surrounding ground water level rising is contained; in the irrigation area, the water level is declined too.